Ken Lerer has two children. His son, Benjamin, started Thrillist, an online men's lifestyle website, and is also a managing director at Lerer Hippeau Ventures. His daughter, Izzie, is founder and CEO of The Dodo, a digital media company for people who care about animals

Lerer is one of the minority owners of the New York Mets, holding a 4% stake in the baseball team.[7]

In 2013, Lerer launched StoptheNRA.com to advocate for the continuation of the assault weapons ban as a federal law. He subsequently donated the website to the Brady Campaign to Prevent Gun Violence.[8]